In summary

Implement smog check for heavy-duty diesel trucks, and enact zero-emission standards on leaf blowers and off-road small engines.

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By Will Barrett

Will Barrett is the senior director for Clean Air Advocacy with the American Lung Association.

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Bill Magavern, Special to CalMatters

Bill Magavern is the policy director for the Coalition for Clean Air.  

Dec. 9 could be the biggest day in recent memory for cleaning up California’s air, if the members of the California Air Resources Board do the right thing. 

Clearly, major actions are needed. More than 9 in 10 Californians live in a county impacted by unhealthy air; 7 of the 10 smoggiest cities in the U.S. are in California; particle pollution kills 5,000 Californians every year.   

These daunting statistics make two facts even harder to stomach: 

One: Leaf blowers and other small off-road engines produce more smog-forming pollution than all the cars in California. In fact, running a gas-powered leaf blower for an hour is like driving from Los Angeles to Denver in terms of smog-forming emissions. 

Two: Heavy-duty diesel trucks don’t go through a basic “smog check” like passenger cars do. That’s despite causing more than half of the pollution on California roads and making up a tiny share of all vehicles on the road.  

Nearly everyone we talk to, whether friends and family, policymakers or journalists, is shocked when they hear these facts.  

Like many Californians, we spent the last year working from our homes and have come to understand how ever-present the drone and stink of leaf blowers can be when one “mow and blow” crew after another rolls through the neighborhood. This class of gasoline engines is so poorly controlled that it now surpasses the smog-forming pollution of all the cars on California roads. That’s bad for our health, and especially bad for workers who are exposed all day.  

Fortunately, the Legislature passed Assembly Bill 1346, authored by Democratic Assemblymembers Marc Berman of Los Altos and Lorena Gonzalez of San Diego, which directs the California Air Resources Board to enact zero-emission standards for new engines as early as 2024. The Legislature also put $30 million on the table to help small landscaping companies transition sooner.  

Our organizations made this shift to zero-emissions a priority this year because it will save lives. The Air Resources Board notes that the rule to implement this law will reduce pollution-related deaths by nearly 900, with overall health benefits reaching $8.8 billion over the course of the rule.  

That’s a big deal. 

The other air pollution head-scratcher is why – despite all of the lifesaving policies California has put in place – heavy-duty diesel trucks don’t face similar smog check requirements as passenger cars. These big rigs represent less than 5% of all vehicles on California roads but generate more than half of the on-road smog-forming pollution and over half of the cancer-causing particle pollution.

Our organizations co-sponsored Sen. Connie Leyva’s 2019 legislation to ensure a robust program would be created. Gov. Gavin Newsom signed Senate Bill 210 into law and the Air Resources Board is poised to adopt the policy on Dec. 9. It is sorely needed, and sorely overdue.  

This measure represents the single most health-protective regulation the board has considered in more than a dozen years. Truck Smog Check is expected to save more than 7,500 lives and generate $75 billion in health benefits. 

This is staggering, and even more so when you think of the predominantly low-income communities and communities of color most impacted by freeways, railyards, warehouses and ports that are heavily dosed by diesel trucks every hour of every day. Those benefits could grow even higher by making sure truck emission controls are confirmed quarterly, an improvement Air Resources Board members should make.  

What’s next? While the governor and Legislature are investing heavily in critical funding for zero-emission transportation and zero-emission standards for cars and trucks are in development for 2022, the oldest, dirtiest diesel trucks need to be retired.  

In Newsom’s Jan. 10 budget proposal, he should invest in the staffing and databases needed to quickly and successfully implement Truck Smog Check. We also need investments in buyback of the oldest, highest polluting trucks while ensuring the landscaping transition to zero-emissions continues in advance of the Air Resources Board’s rule. 

These steps would pay off in cleaner air for Californians for years to come. 


Bill Magavern has also written about the need for California to eliminate its reliance on diesel backup generators and a plan to expand access to electric vehicles.

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